1. Field of the Invention
The present invention relates, generally, to a peripheral device for electronic equipment and, more particularly, to a panel-type or panel-shaped peripheral device constructed as, e.g., an input or display unit. The present invention also relates to a method of producing such a panel-type peripheral device, as well as to certain equipment usable for performing the producing method.
2. Description of the Related Art
Recently, in the technical field of digital data processors with displays, such as personal computers, word processors, electronic notebooks, personal digital assistants (PDAS), etc., a panel-type or panel-shaped input unit, referred to as a touch panel, adapted to be arranged over a screen of a display unit, such as a liquid crystal display (LCD), a plasma display panel (PDP), a cathode ray tube (CRT), has been widely used. In the panel-type input unit or touch panel, an operator presses with his finger or a pen on a desired point on a panel surface, and thereby enters or directs two-dimensional coordinate data on the display screen.
The conventional touch panel includes a pair of plate-shaped detecting elements or conductive panel members, each of which is provided with a transparent insulating substrate and a transparent conductive film formed on the surface of the insulating substrate. The detecting elements are fixed together, in a state where the conductive films thereof oppositely face to each other through a certain gap, by a strip-shaped adhesive layer provided to extend along the outer peripheries of the opposed insulating substrates. The gap between the detecting elements is obtained due to the adhesive layer and a large number of dot spacers dispersedly arranged on the surface of the conductive film of one detecting element. The dot spacers serve to prevent each detecting element from being deformed at least due to its own weight so as to maintain the gap between the detecting elements, while permitting the conductive films to come into contact with each other when either one of the detecting elements is deformed by an external pressing force. Typically, the insulating substrate of the upper detecting element adapted to be pressed by the operator is made of a resinous film to meet the requirement of flexibility, and the insulating substrate of the lower detecting element adapted to be disposed adjacent to a display screen is made of a glass pane, a plastic plate, a resinous film, etc.
Another touch panel including the above-described basic structure has been also known, wherein a transparent insulating liquid material having a refractive index equivalent to that of each detecting element is filled and sealed in the gap between the pair of detecting elements so as to improve the optical transmittance of the touch panel and thus improve the visibility of a display screen. Such a liquid-sealing touch panel has a structure similar to a liquid crystal cell of a conventional LCD. Therefore, it is possible to pour the liquid material into the gap between the detecting elements in a way similar to a liquid-crystal pouring operation in a conventional process for manufacturing the LCD.
The liquid-crystal pouring operation in the conventional LCD manufacturing process includes following steps. First, a panel assembly is provided, in which a pair of electrode plates or conductive panel members, each including an insulating substrate and a conductive film formed on one surface of the insulating substrate, are fixed to each other in a state where the respective conductive films of the electrode plates oppositely face to each other through a certain gap. The panel assembly is an unfilled liquid crystal cell, in a condition before the liquid crystal is poured, and is referred to, e.g., as an empty cell. The pair of electrode plates are fixed together by a strip-shaped adhesive layer provided between the mutually opposing surfaces of the insulating substrates of the electrode plates to extend along the outer peripheries of the insulating substrates. A passage is formed adjacent to the adhesive layer as, e.g., a cut-out portion of an adhesive, for communicating the gap between the electrode plates to an environment outside of the empty cell. The adhesive layer serves to hermetically seal the gap between the electrode plates against the outside environment at a region other than the passage.
Next, a receptacle accommodating a liquid crystal material is provided, and the receptacle and the panel assembly as described are placed in a common outside environment, such as a sealed chamber. Then, the sealed chamber is evacuated to depressurize the outside environment while the passage formed in the panel assembly is exposed to the outside environment, so as to evacuate the gap between the electrode plates of the panel assembly and to vacuum-degas the liquid crystal material. Subsequently, the passage of the panel assembly and the area adjacent thereto are immersed into the liquid crystal material in the receptacle under the outside environment as depressurized. At this time, the liquid crystal material slightly permeates into the gap between the electrode plates through the passage in the panel assembly due to a capillary action. Thereafter, an inert gas is introduced into the sealed chamber to increase a pressure therein, and thereby entirely filling the gap with the liquid crystal material.
When a procedure similar to the above-described liquid-crystal pouring operation in the conventional LCD manufacturing process is applied to the liquid pouring operation in the liquid-sealing touch panel as described, which is constructed by assembling the upper detecting element including a resinous-film insulating substrate and the lower detecting element including a glass-pane insulating element, the upper detecting element tends to be bent toward the lower detecting element due to a pressure rise during the time when the insulating liquid material is filled into the gap in the panel assembly by increasing the pressure of the outside environment. If such a deformation is caused in one of the detecting elements of the panel assembly in a liquid filling step, the gap between the detecting elements is narrowed, which may result in a difficulty in the rapid filling of the insulating liquid material entirely into the gap, and may cause a touch panel, as a finished product after the filling step is completed, to have a slightly concave center area of the upper detecting element relative to the outer peripheral area thereof. Such a concave upper detecting element may result in a distortion in a transmitted image through the touch panel especially in an area adjacent to the outer periphery thereof, as well as may result in an indeterminately separated state of the detecting elements after they separate from each other for conduction at a pressed point.
It may be predicted that the above-described problems remarkably arise in the case where both detecting elements of the touch panel include resinous-film insulating substrates. Also, it may be predicted that the concave center area of a flexible conductive panel member is generated, during a liquid material pouring operation, not only in the liquid-sealing touch panel, but also in various liquid-sealing panel-type peripheral devices, such as a liquid crystal display using a resinous-film substrate, wherein at least one of the conductive panel members of a panel assembly has a flexibility for permitting a relatively easy deformation due to a pressure fluctuation in the outside environment.
In the above-described liquid pouring operation, the panel assembly and the liquid material are placed in a depressurized environment in the step of pouring the liquid material into the gap between the conductive panel members of the panel assembly, so that it is a precondition that a liquid material having a sufficiently low vapor pressure, such as a silicone oil, is used. Accordingly, the range of selection of the liquid material is narrow, and thereby the structural optimization of the panel-type peripheral device, such as a selection of the liquid material having a chemical stability in relation to the materials of various components of the panel assembly, may be restricted.
Incidentally, in the conventional liquid-sealing panel-type peripheral device, the passage for pouring the liquid material, formed between the pair of conductive panel members adjacent to the adhesive layer, linearly extends and has a uniform cross-section, in general, between an interior port opening to the gap between the conductive panel members and an exterior port opening to the outside environment. The passage of this shape has an advantage that, in the case where the adhesive layer is formed by a pressure sensitive adhesive double-coated tape, it is possible to significantly easily form the passage by a cut-out portion of the double-coated tape. However, the conductive panel members are not fixed to each other in the region of the passage, so that, in the case where one of the conductive panel members or detecting elements includes a resinous-film insulating substrate, such as in the touch panel, it may be difficult to securely hold this conductive panel member in the vicinity of the passage.
Particularly, it is required, in the touch panel, that the upper detecting element to be pressed for operation is securely held while a uniform tension is entirely applied thereto, so as to ensure that data is accurately and stably entered irrespective of a pressed position. Therefore, it is preferred that the passage for pouring the liquid material is formed as narrow as possible, but the reduction of the cross-section of the passage may increase the time required for the operation of filling the liquid material. In this respect, it may be advisable that plural narrow passages are dispersedly formed at certain positions, but this arrangement may complicate a passage sealing operation performed after the liquid material filling operation is finished.
It is therefore an object of the present invention to provide a method of producing a panel-type peripheral device including a pair of conductive panel members and a liquid material filled and sealed in a gap between the conductive panel members, wherein, even when at least one of the conductive panel members has a flexibility for permitting a relatively easy deformation due to a pressure fluctuation in an outside environment, it is possible to quickly and entirely fill the gap between the conductive panel members with the liquid material in a liquid material pouring operation, without generating a concave center area of the flexible conductive panel member.
It is another object of the present invention to provide a method of producing a panel-type peripheral device including a pair of conductive panel members and a liquid material filled and sealed in a gap between the conductive panel members, wherein it is possible to select various liquid materials without being restricted by a vapor pressure, and thus to facilitate the structural optimization of the peripheral device.
It is still another object of the present invention to provide certain equipment preferably usable for performing the above-described producing method.
It is further object of the present invention to provide a panel-type peripheral device produced by above-described producing method, which exhibits a superior functionality, and particularly, to provide a touch panel ensuring little distortion in a transmitted image as well as an accurate and stable entering operation.
It is still further object of the present invention to provide a panel-type peripheral device, particularly a touch panel, including a pair of conductive panel members and a liquid material filled and sealed in a gap between the conductive panel members, wherein it is possible to prevent a function thereof from being deteriorated due to the existence of a passage for pouring the liquid material, without complicating a liquid filling operation and a passage sealing operation.
In accordance with the present invention, there is provided a method of producing a panel-type peripheral device including a pair of conductive panel members, each conductive panel member being provided with an insulating substrate and a conductive film on a first side of the insulating substrate, comprising providing a panel assembly including the pair of conductive panel members fixed to each other with respective conductive films thereof oppositely facing to each other through a gap defined therebetween, the panel assembly having a passage for communicating the gap with an environment outside of the panel assembly, the gap being hermetically sealed against the environment at a region other than the passage; providing a support member having a rigidity higher than that of at least one of the conductive panel members of the panel assembly, the support member including a support surface larger than a second side of the insulating substrate, opposite to the first side, of the at least one of conductive panel members; providing a receptacle accommodating a liquid material; placing the panel assembly, the support member and the receptacle in a common environment; securely arranging the support member over and adjacent to the at least one of conductive panel members of the panel assembly with the support surface oppositely facing to the second side of the insulating substrate; depressurizing the common environment while the passage of the panel assembly is exposed to the common environment, to evacuate the gap in the panel assembly; immersing the passage of the panel assembly into the liquid material in the receptacle under the common environment as depressurized; and increasing a pressure of the common environment as depressurized, to cause a flow of the liquid material from the receptacle into the gap in the panel assembly through the passage, and to fill the gap with the liquid material, without directly applying the pressure of the common environment onto the at least one of conductive panel members arranged adjacent to the support member.
In this method, it is preferred that the step of securely arranging the support member over and adjacent to the at least one of conductive panel members of the panel assembly includes defining a second gap between the support surface of the support member and the second side of the insulating substrate of the at least one of conductive panel members, that the step of depressurizing the common environment includes communicating the second gap to the common environment, and that the step of increasing the pressure of the common environment includes hermetically sealing the second gap against the common environment.
Also, in this method, it is advantageous that the at least one of conductive panel members of the panel assembly, securely arranged over and adjacent to the support member, has a flexibility for permitting a relatively easy deformation due to a pressure fluctuation in the common environment.
The present invention also provides a panel-type peripheral device produced by the above-described method.
The present invention also provides a panel support unit comprising the support member provided in the above-described method.
The panel support unit may further comprise a second support member cooperating with the support member to securely support the panel assembly.
The present invention also provides a panel support unit comprising the support member provided in the above-described method; a vent hole for communicating the second gap with the common environment; and a valve member capable of opening and closing the vent hole in response to a pressure fluctuation in the common environment.
In another aspect of the present invention, there is provided a method of producing a panel-type peripheral device including a pair of conductive panel members, each conductive panel member being provided with an insulating substrate and a conductive film on a first side of the insulating substrate, comprising providing a panel assembly including the pair of conductive panel members fixed to each other with respective conductive films thereof oppositely facing to each other through a gap defined therebetween, the panel assembly having a passage for communicating the gap with an environment outside of the panel assembly, the gap being hermetically sealed against the environment at a region other than the passage, at least one of the conductive panel members having a flexibility for permitting a relatively easy deformation due to a pressure fluctuation in the environment; providing a partition wall including a through opening, into which a part of the panel assembly is capable of being fitted in a hermetically sealed manner; fitting the part of the panel assembly into the through opening of the partition wall, in a hermetically sealed manner, in such a manner that the passage of the panel assembly opens to one side of the partition wall, and that major parts of the conductive panel members of the panel assembly are located in another side of the partition wall; placing a liquid material in the one side of the partition wall; immersing an open portion of the passage of the panel assembly, fitted into the through opening of the partition wall, into the liquid material; increasing a pressure of an environment in the other side of the partition wall to deform the at least one of the conductive panel members of the panel assembly, to evacuate the gap in the panel assembly; and decreasing a pressure of the environment in the other side of the partition wall to deform the at least one of conductive panel members of the panel assembly, to cause a flow of the liquid material from the one side of the partition wall into the gap in the panel assembly through the passage, and to fill the gap with the liquid material.
In this method, it is preferred that the partition wall includes a plurality of through openings, into which respective parts of a plurality of panel assemblies are capable of being fitted in a hermetically sealed manner, and that the gap of each of the panel assemblies is simultaneously filled with the liquid material.
The present invention also provides a panel-type peripheral device produced by the above-described method.
The present invention also provides a liquid pouring system comprising the partition wall provided in the above-described method.
The liquid pouring system may further comprise a liquid-material storing vessel provided in the one side of the partition wall, a pressure regulating chamber provided in the other side of the partition wall, and a support mechanism for securely supporting the panel assembly in a state where the part of the panel assembly is fitted into the through opening of the partition wall.
In a further aspect of the present invention, there is provided a method of producing a panel-type peripheral device including a pair of conductive panel members, each conductive panel member being provided with an insulating substrate and a conductive film on a first side of the insulating substrate, comprising: providing a panel assembly including the pair of conductive panel members fixed to each other with respective conductive films thereof oppositely facing to each other through a gap defined therebetween, the panel assembly having a passage for communicating the gap with an environment outside of the panel assembly, the gap being hermetically sealed against the environment at a region other than the passage; providing a wall including a through opening, into which a part of the panel assembly is capable of being fitted; fitting the part of the panel assembly, into the through opening of the wall, in such a manner that the passage of the panel assembly opens to one side of the wall; depressurizing an environment in both sides of the wall to a vacuum condition; placing a liquid material in the one side of the wall to immerse an open portion of the passage of the panel assembly into the liquid material; and flowing the liquid material from the one side of the wall into the gap in the panel assembly through the passage by a function of gravity, to fill the gap with the liquid material.
In this method, it is preferred that the wall includes a plurality of through openings, into which respective parts of a plurality of panel assemblies are capable of being fitted, and that the gap of each of the panel assemblies is simultaneously filled with the liquid material.
Also, in this method, it is preferred that the wall is capable of closing between the one side and the other side in a hermetically sealed manner, and further comprises a step of varying a pressure of the environment in the other side of the wall, after the gap of the panel assembly is filled with the liquid material, to adjust a volume of the liquid material in the gap.
The present invention also provides a panel-type peripheral device produced by the above-described method.
The present invention also provides a liquid pouring system comprising the wall provided in the above-described method.
The liquid pouring system may further comprise a liquid-material storing vessel provided in the one side of the wall, a pressure regulating chamber continuously formed around the wall and the liquid-material storing vessel, and a support mechanism for securely supporting the panel assembly in a state where the part of the panel assembly is fitted into the through opening of the wall.
In the above-described various methods, the panel-type peripheral device may have a configuration of a touch panel including a pair of detecting elements as the pair of conductive panel members, each detecting element being provided with a transparent insulating substrate and a transparent conductive film on a first side of the insulating substrate, and at least one of the detecting elements of the panel assembly, securely arranged over and adjacent to the support member, may have a flexibility for permitting a relatively easy deformation due to a pressure fluctuation in the common environment, and the liquid material may be a transparent insulating liquid material.
In a yet further aspect of the present invention, there is provided a panel-type peripheral device comprising a pair of insulating substrates spaced from and opposed to each other; a pair of conductive films respectively formed on opposed surfaces of the insulating substrates to face oppositely to each other through a gap; an adhesive sealing member for sealing the gap against an outside environment and fixing the insulating substrates with each other; and a liquid material filled and sealed in the gap; wherein the adhesive sealing member includes a strip-shaped adhesive layer laminated on the opposed surfaces of the insulating substrates to extend along outer peripheries of the insulating substrates; at least one passage formed adjacent to the adhesive layer for pouring the liquid material into the gap; a sealant for sealing the at least one passage; each of the at least one passage being provided with one exterior port opening to the outside environment and at least one interior port independently opening to the gap, each interior port having an opening area smaller than the exterior port.